Fibrous substrates

ABSTRACT

A fibrous security substrate for use in producing documents includes at least one aperture extending therethrough and contains an elongate impermeable element at least partially embedded therein such that at least one edge thereof is exposed in the aperture.

This application is a 371 of PCT/GB03/02723, filed Jun. 25, 2003 whichclaims priority of United Kingdom Patent document 0214645.4, filed Jun.25, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to improvements in methods of making fibroussubstrates, and in particular to such substrates containing an elongateimpermeable element which can be easily verified through an aperture inthe substrate.

2. The Prior Art

It is generally known to include elongate security elements in securitypaper, as a security feature. Such elements can be threads, strips orribbons of, for example, plastics film, metal foil, metallised plastic,metal wire. These security elements are included in the thickness ofsecurity paper to render imitation of documents produced from the papermore difficult. These elements help in the verification of securitydocuments as they render the view of the documents in reflected lightdifferent from that in transmitted light. To increase the securityprovided by the inclusion of such an elongate element, it is also knownto endow the element itself with one or more verifiable properties overand above its presence or absence. Such additional properties includemagnetic properties, electrical conductivities, the ability to absorbx-rays and fluorescence.

As a further security feature, it has been found to be particularlyadvantageous to provide windows in one side of the surface of the paper,which expose such elongate elements at spaced locations. Examples ofmethods of manufacturing such paper incorporating security elements withor without windows are described below. It should be noted thatreferences to “windowed thread paper” include windowed paperincorporating any elongate security element.

EP-A-0059056 describes a method of manufacture of windowed thread paperon a cylinder mould paper-making machine. The technique involvesembossing the cylinder mould cover and bringing an impermeable elongatesecurity element into contact with the raised regions of an embossedmould cover, prior to the contact entry point into a vat of aqueousstock. Where the impermeable security element makes intimate contactwith the raised regions of the embossing, no fibre deposition can occur.After the paper is fully formed and couched from the cylinder mouldcover, the water is extracted from the wet fibre mat and the paper ispassed through a drying process. In the finished paper the contactpoints are present as exposed regions which ultimately form windows,visible in reflected light, on one side of a banknote paper.

WO-A-93/08327 describes a method of manufacturing windowed thread paperon a Fourdrinier paper-making machine. A rotating embedment means, witha modified profile for embossing, is used to drive an impermeableelongate security element into draining paper stock, on a Fourdrinierwire. The profile of the embedment means is such that raised portionsare provided which remain in contact with the security element duringthe embedment process. Thus, paper fibres are prevented from collectingbetween the security element and embedment means, such that the securityelement is subsequently exposed in windowed regions of paper.

The aforementioned processes enable paper to be manufactured in whichthe security element is exposed in windows in one surface of the paper,or in windows in both surfaces at alternating positions, or to formapertures whereby the windows on the front of the document are inregister with those on the back. In order for a user to confirm thesecurity element is continuous and running within the paper they mustview the paper in transmitted light. However, users frequently tear thepaper in the region of the security element to determine its presence,rather than viewing it in transmission. As a result documents containingsecurity elements are commonly prematurely and deliberately damaged.

The object of the present invention is to provide a security substrateincorporating an elongate security element in which the elongate elementis very easily verifiable from both sides of the substrate in apertureswhich extend through the substrate.

SUMMARY OF THE INVENTION

The invention therefore provides a substrate having an elongate elementpartially embedded therein and at least one discrete aperture extendingthrough the fibrous substrate exposing at least a part of the elongateelement, wherein at least one edge of the elongate element is exposed inthe aperture(s).

The invention also provides a method of making a fibrous substratehaving an elongate element partially embedded therein, comprising thesteps of providing drainage restriction areas on a porous supportsurface, depositing fibres on to the porous support surface around thedrainage restriction areas to form a first layer, bringing the elongateelement to lie in contact with the drainage restriction areas of thesupport surface, and depositing further paper fibres over the firstlayer to securely embed segments of the elongate element within thesubstrate between the drainage restriction areas, said drainagerestriction areas being such as to substantially prevent the depositionof fibres thereon before and after the elongate element is laidthereover and to thereby form at least one discrete aperture extendingthrough the fibrous substrate, wherein at least one edge of the elongateelement is exposed in the aperture(s).

Preferred embodiments of the present invention will now be described, byway of example only, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a security document made from a substrateaccording to the present invention;

FIGS. 2 to 7 are cross-sectional side elevations of steps involved inthe method of making a fibrous substrate according to the presentinvention;

FIGS. 8, 9, and 11 to 13 are plan views of alternative embodiments ofthe substrate of FIG. 1;

FIG. 10 is a cross sectional side elevation of the substrate of FIG. 9;

FIG. 14 is a plan view of pages cut from the substrate of FIG. 1 to beused to provide a booklet;

FIG. 15 is a plan view of a sheet of the substrate made by the presentinvention to be cut into smaller sheets; and therefor.

FIG. 16 is a plan view of a sheet cut from the subsrate of FIG. 15.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The fibrous substrate 16 according to the present invention isillustrated in FIG. 1 and comprises an elongate security element 13partially embedded within the substrate 16, having one or more apertures17 extending through the substrate 16 exposing short lengths of thesecurity element 13. In other embodiments of the invention, for exampleas shown in FIGS. 8, 9, 10 and 12, the width and/or the positioning ofthe security element 13 is such that only one edge of the element 13 isexposed in the aperture(s) 17.

The method of manufacturing a security substrate according to thepresent invention is illustrated firstly with reference to FIGS. 2 to 7.A porous support surface, for example in the form of a cylinder mouldcover 10, is produced in a known way. The mould cover 10 has a pluralityof drainage restriction regions 12. These can, for example, be providedby fixing a blinding material to the mould cover 10. The blindingmaterial is typically a metal which is welded to the cylinder mouldcover 10 (see FIG. 3). Other suitable blind materials are wax, polymeror any other material which can be securely attached to the cylindermould cover 10 to prevent drainage of water from fibrous stock 11 andhence fibre deposition. These drainage restriction regions 12 define theshape of the apertures 17 formed in the final substrate 16.

In a known manner, the cylinder mould cover 10 is rotated in a vat offibrous stock 11 as illustrated in FIG. 2. As it rotates, an elongatesecurity element 13 is brought into contact with the cylinder mouldcover 10 below the level of the fibrous stock 11. This means that alayer 14 of fibres has already been deposited onto the cylinder mouldcover 10 to form, say, a 40 gsm sheet (see FIGS. 4 and 5). Once thesecurity element 13 is brought into contact with the drainagerestriction regions 12, further fibres 15 are deposited on top of thelayer 14 to form the remainder of the substrate 16 to, typically, 80 to90 gsm (see FIGS. 5 and 6). It should of course be noted that inpackaging applications the substrates used can have much highergrammages, for example in the order of 250 gsm.

The positioning of the security element 13, with respect to the drainagerestriction regions 12 must be determined in the context of whether theelement 13 is to be wholly or partly exposed in the apertures 17 (i.e.one edge or both) and this may be affected by the width of the element13 also.

The security element 13 may be impermeable, if it is to be exposed alongboth of its edges as shown in FIG. 1. However it may have a permeableportion 30, as shown in FIGS. 9 and 10, if the element 13 is to haveonly one edge exposed and the element 13 is relatively wide as comparedwith the width of the aperture 17. The permeable portion 30 helps toanchor the element 13 within the substrate 16. Alternatively, a layer ofadhesive may be provided on the element 13 instead of the permeableportion 30, to assist in anchoring it within the substrate 16.

The security element 13 preferably has-a width of at least 0.5 mm, andmore preferably in the range of 0.5 mm to 6 mm, and more preferably inthe range of 0.5 mm to 2 mm.

Thus, as mentioned above, a layer of fibres is laid down on the cylindermould cover 10 prior to the introduction of the security element 13.However, whilst the drainage restriction regions 12 would retain littleor no covering of paper fibres before the elongate element 13 is broughtinto contact therewith, full coverage is obtained in the surroundingareas between the drainage restriction regions 12. Equally, because ofthe impermeable nature of the elongate element 13 and the drainagerestriction regions 12, there is little or no covering of fibresretained over the area occupied by the drainage restriction regions 12,after the element 13 has been brought into contact. During the formationof the apertures 17, some fibres may deposit in the gaps on either sideof the elongate element 13 which is narrower than the width of thedrainage restriction regions 12 (designated by numeral 19 in FIG. 6).However because of the drainage restriction regions 12, the substrate 16cannot properly form in the region 19. If required, any such unwantedfibres may be removed during subsequent processing steps.

Thus, when the substrate 16 is removed from the cylinder mould cover 10(see FIG. 7), whilst the substrate 16 incorporates the elongate element13, the elongate element 13 is exposed in apertures 17 extending throughthe substrate corresponding to the drainage restriction regions 12.Segments 18 of the elongate element 13, between the apertures 17, arewholly embedded within the substrate 16.

In a modification of the present invention, the cylinder mould cover 10is produced in a known way, using dies to form the wire by embossing toform one or more raised areas, which define the shape of the apertures17 in the final substrate 16. The peaks of the raised areas are thenprovided with drainage restriction regions 12 to form the apertures 17.

One preferred material for the element 13 is a PET strip of, say, 50microns thickness as this would help to maintain the “bulk” of the paper16 over the windowed region. However, other materials such as OPP, PE orPET with other thicknesses may be used. Typically anything from 12microns upwards can be used.

Alternative embodiments of the invention is illustrated in FIGS. 11 and12, in which the apertures 17 are used in conjunction with traditionalwindows 25, as described in EP-A-0059056, EP-A-0229645 and EP-A-0625431,in which neither edge of the security element 13 is exposed. FIG. 11shows both edges of the element 13 exposed in an aperture 17, whilstFIG. 12 shows only one of its edges exposed.

The elongate element 13 may be used as a display surface for indicia,for example de-metallised images, holographic images, colour-shiftingareas, print or combinations of any or all of these which are highlyvisible in the apertures 17. The element 13 may include differentsecurity features along its length, such that a different feature can beseen in consecutive apertures 17.

When viewed from either side of the substrate 16, the security element13 itself can be seen in the apertures 17 as a transparent, shiny,coloured or metallised area which may bear indicia, information and/orimagery. More specific examples include the following:

-   -   de-metallised security elements 13, which may comprise areas of        substantially removed metal to take advantage of the        transparency of the base film and provide a large area of        transparency in the aperture 17;    -   holographic security elements 13, which could comprise areas of        full metal and half-tone screens to provide partial transparency        and/or no metal. Under certain viewing conditions, with no        metal, a holographic image is still visible in the aperture 17.        Coatings, such as ZnS, having a high refractive index may also        be used instead of metal as the reflection enhancing layers.        These coatings are essentially transparent;    -   security elements 13 with front to back print registration, in        which features are printed which would clearly exhibit Moiré        patterns from both front and back if a counterfeit were        attempted. Alternatively, such patterns could be produced on a        transparent film prior to insertion of the security element 13        into the paper as a security feature itself. The exact        reproduction of such patterns are very difficult to mimic;    -   security elements 13 with different coloured print showing on        the front to the back. The print may be on either side of the        security element 13 or both on the same side, with one colour        hidden by the other on one side but showing through on the other        side;    -   security elements 13 comprising or having coatings of liquid        crystal, colourshift, thermochromic, photochromic, and        iridescent materials to exhibit colour changes within the        apertures;    -   security elements 13 comprising or having coatins of luminescent        or magnetic materials;    -   security embossing of a transparent film forming the base of the        security element 13 with a security design (e.g. a latent images        such as those disclosed in EP-A-433330) created during the        printing process. These may be blind embossed to produce a        tactile/visible feature or could include printing inks to        further enhance visibility;    -   security elements 13 have, a matt coating of a similar; colour        to the substrate, such that it is only visible in the apertures        17 or any windows 25;

The paper 16 described above can be cut and printed to make all forms ofdocuments, including security documents such as banknotes, cheques,travellers cheques, identity cards, passports, bonds etc or non-securitydocuments such as stationary, labels etc.

The positioning of the apertures 17, and therefore the design of thedrainage restriction regions 12, can be such that when a continuoussheet of fibrous substrate 16 is finished and cut to form discretesheets, each discrete sheet may have one or a plurality of apertures 17therein. Within each aperture 17 the security element 13 can clearly beseen extending from one side to the other of the apertures 17 (in themachine direction of the paper). The apertures 17 may be circular asillustrated in the accompanying drawings, or any other shape, forexample as shown in FIG. 13. The apertures 17 may also definecharacterising information, such as indicia, logos or the like. Theshape of the apertures 17 may also relate to information elsewhere onthe document, such as print and/or security devices.

Where sheets made from the substrate 16 are intended to be used in theform of a booklet, for example as pages of a passport, the sheets may becut to include a single aperture 17 on each sheet, but at staggeredpositions. When the sheets are bound together in the booklet, flickingthrough the pages at a reasonable speed would give the impression of anaperture moving and therefore provides a simple form of verification.This is illustrated in FIG. 14 with three pages 20, 21 and 22, whichwill be bound together along the left hand edges. Any missing pageswould clearly show the aperture movement out of sequence and thereforeprovide an anti-tamper feature.

The security element 13 may also be used as part of a selfauthenticating feature, such as those described in EP-A-0930979 orEP-A-0256176.

The substrate 16 may also be cut in a manner which provides half anaperture 17 along one or more edges of a discrete sheet cut from thesubstrate 16. As shown in FIG. 15 substrate 16 can be cut into twoseparate discrete sheets 23, 24 along the line XX. As this cutting linepasses through the aperture 17 and elongate element 13, a notch will beleft in the edge of each of the sheets 23, 24 in which an end of theelongate element 13 is exposed, as shown in FIG. 16.

1. A fibrous security substrate for producing documents, said fibroussecurity substrate including an elongate element partially embeddedtherein and a discrete aperture extending through the fibrous substrateso as to expose at least a part of the elongate element, wherein atleast one edge of the elongate element is exposed in the aperture, a gapbeing formed between the elongate element and a perimeter of theaperture.
 2. A substrate as claimed in claim 1 in which the elongateelement bears indicia, images or information.
 3. A substrate as claimedin claim 1 in which the elongate element is wholly or partiallymetallised.
 4. A substrate as claimed in claim 1 in which the elongateelement bears one or more holographic images.
 5. A substrate as claimedin claim 1 in which the elongate element has at least one colour shiftareas.
 6. A substrate as claimed in claim 1 in which the elongateelement has at least one security embossing.
 7. A substrate as claimedin claim 1 in which the elongate element is printed on one or bothsides.
 8. A substrate as claimed in claim 1 in which the elongateelement bears a liquid crystal material.
 9. A substrate as claimed inclaim 1 in which at least another part of the elongate element isexposed in one or more windows in at least one surface of the substrate.10. A document made from a fibrous substrate according to claim 1comprising at least one aperture.
 11. A document as claimed in claim 10comprising a plurality of apertures.
 12. A document as claimed in claim10 comprising a security document selected from the group consisting ofa banknote, a cheque, a travelers cheque, an identity card, a passportand a bond.
 13. A document as claimed in claim 10 in which the documentis a non-security document selected from the group consisting of an itemof stationery and a label.
 14. A document comprising a plurality ofsheets which are each made from a fibrous substrate according to claim1, the aperture in each sheet of said plurality of sheets being inregister with the aperture in adjacent sheets.
 15. A document comprisinga plurality of sheets which are each made from a fibrous substrate thathas a discrete aperture extending therethrough and has an elongateelement partially embedded therein such that at least one edge of theelongate element is exposed in said aperture and a gap is formed betweenthe elongate element and a perimeter of the aperture, the aperture ineach sheet of said plurality of sheets being in a location offset withrespect to the location of the aperture in adjacent sheets.
 16. Adocument which includes a fibrous security substrate that has a apertureextending therethrough and an elongate element partially embeddedtherein such that at least one edge of the elongate element is exposedin said aperture and a gap is formed between the elongate element and aperimeter of the aperture, at least a part of the aperture being locatedalong an edge of the document.
 17. A method of making a fibroussubstrate as claimed in claim 1 having an elongate element partiallyembedded therein, comprising the steps of providing drainage restrictionareas on a porous support surface, depositing fibres on the poroussupport surface around the drainage restriction areas to form a firstlayer, bringing the elongate element to lie in contact with the drainagerestriction areas of the support surface, and depositing further paperfibres over the first layer to securely embed segments of the elongateelement within the substrate between the drainage restriction areas,said drainage restriction areas being such as to substantially preventthe deposition of fibres thereon before and after the elongate elementis laid thereover and to thereby form at least one discrete apertureextending through the fibrous substrate, wherein a width of the elongateelement is less than a maximum width of the aperture(s).
 18. A method asclaimed in claim 17 further comprising the step of forming at least onewindow in at least one surface of the substrate in which a portion ofthe elongate element, not including either of its edges, is exposed.